Research on high-yielding cassava for smallholder farmers in Thailand


Farmer Enrolment

In December 2016, a team of 4 from Carmiel Agrotech Sdn Bhd (CASB) undertook a research project with Vana in the provinces of Rayong and Nakhon in Thailand, and visited the Rayong Field Crops Research Centre (RFCRC) to study Thailand’s high yielding cassava varieties to be replicated and propagated in Sierra Leone for smallholder farmers working with Sunbird Bioenergy Sierra Leone (SBSL).

SBSL was in its transition from using sugarcane as a feedstock for bio-ethanol to using cassava. However, the cassava yields for smallholder farmers in Sierra Leone is found to be less than 25 tonnes/ha, whereas in Thailand they are as high as 90 tonnes/ha despite having similar agroclimatic conditions.


SBSL owns over 9000 Ha. of land in the Tonkolili District in Sierra Leone. It currently cultivates sugarcane to be used as feedstock in producing bio-ethanol. Due to low yields and high maintenance costs, SBSL is not profitable using sugarcane as a feedstock and aims to move to cassava. The move to cassava will cost SBSL USD 55 million in capital costs. Vana will be managing the cassava outgrower program for SBSL. CASB has been approached by SBSL and Vana to do a feasibility study on the varieties currently available in Sierra Leone and varieties that would be better as feedstock.

Results of the Research

  • Current sugarcane to ethanol conversion rate in the factory in Mabilafu is 1 tonne or sugarcane to .08 tonnes of ethanol. It is proposed that switching to cassava will improve this coversion to .16 tonnes of ethanol which is roughly double the previous conversion rate.
  • CASB suggests that a dynamic cassava outgrower program will help in achieving the target of 120,000 tonnes of bio-ethanol.
  • Additionally, the starch and pulp from the cassava can be used to generate electricity at the rate of 22.28 mW/hr. Post home consumption, the sale of the excess electricity can generate and additional income of USD 15 million.
  • To move to cassava, SBSL needs to build a saccarification front end addition which will cost 55 million and take 8 months.
  • Cassava, being a local staple is relatively easier for the local farmers to cultivate as opposed to sugarcane. However, the yields of the local varieties are very low. Since cassava is grown mostly for human consumption and not for extracting ethanol, the varieties have very low starch content.
  • For the extraction of ethanol, the starch content needed in the cassava is 24-30% and the yield per acre should be between 60-80 tonnes. Varieties that can give these results are available in Thailand, Indonesia, India and Nigeria.
  • Thailand and Sierra Leone lie along the same latitudes and recieve the similar rainfall distribution although Rayong recieves more rainfall all around the year than Makeni. To counter this, CASB and Vana suggest using drip irriagation for the cultivation of Cassava.
  • In Rayong, among the local farmers with nil or low irrigation and fertlizer inputs, the cassava yields have been found to be 30 tonnes per hectare with a starch content of 25-30%. With adequate irrigation and fertilizers, a high official in RFCRC claims that yields can improve to 90 tonnes per hectare.
  • To minimise failure in germination, Vana and CASB propose tissue culture for cassava as opposed to the traditional method of transplantation.
  • A huge factor for the move to cassava is the inability to store sugarcane for prolonged periods of time. Post-harvest, sugarcane needs to be processed as soon as possible but cassava, after chipping and drying can be stored for upto 4 years.

CASB and Vana suggested the use of Rayong-9 variety of cassava for cultivation inside the estate as well as for the cassava outgrower programme in Makeni.

Role of Vana

As proposed by the agronomists, SBSL agreed to transition from sugarcane to cassava for the feedstock in their bioethanol plant. The seed material for the smallholder farmers and the estate will initially be provided by Vana‘s partner Terravana Seeds. Importing seed material from Thailand is not a viable option for SBSL in the long run. CASB has proposed a tissue culture laboratory in Sierra Leone to import Rayong-9 germplasm and propagate invitro to produce high-yielding seed material. This seed material will be supplied to Vana‘s farmers for cultivation. The CASB team also studied the cultivation methods adopted in Thailand, the tools and equiment which help in efficient planting, weeding and harvesting. Vana plans to make these available to farmers in Sierra Leone through its partners.

Next Steps

CASB is in the process of setting up a tissue culture lab in SBSL‘s estate. Vana plans to recruit smallholder farmers for cultivation. A detailed training program for the farmers is being developed at the Vana Research and Innovation Centre (VRIC), Malaysia.